Reduced graphene oxide coated manganese dioxide electrode prepared by polyvinylpyrrolidone assisted electrodeposition

Abstract

In this work, reduced graphene oxide coated manganese dioxide electrode (MnO2@rGO) is prepared by polyvinylpyrrolidone (PVP) assisted electrodeposition, which contributes the excellent performance in supercapacitor and lithium-ion battery (LIB). In detail, MnO2 electrode is firstly prepared by employing electrochemical deposition method with PVP as auxiliary agent. Appropriate PVP concentration can induce the form of MnO2 nanosphere morphology to improve efficiently the electrochemical performance of MnO2 electrode. Then, the reduced graphene oxide (rGO) film is coated on the surface of the electrode by electrochemical reduction to finally obtain PVP assisted MnO2@rGO composite electrode (denoted by MnO2&PVP@rGO). The specific capacitance of MnO2&PVP@rGO used as supercapacitor is 358 F⋅g−1 at 1 A . g-1 current density, which is double higher than the specific capacitance (178 F⋅g−1) of pure MnO2 electrode. When MnO2&PVP@rGO is adopted as the anode material of LIB, the specific capacity of 1024 mAh⋅g−1 is maintained after 450 cycles at the current density of 1 A⋅g−1. The electrode (used as LIB anode) still shows a high specific capacity of 375 mAh⋅g−1 under the high current density of 5000 mA⋅g−1, which is 4.6 times that of the MnO2 prepared under ordinary conditions.